Orthodontics is a specialized area of dentistry concerned with the diagnosis and treatment of dental malocclusions to improve bite function, hygiene, and facial aesthetics. Orthodontic therapy commonly uses appliances called brackets and molar tubes which are bonded to a patient's teeth. Brackets and molar tubes contain slots and passageways, respectively, to accommodate a resilient “U”-shaped wire called an orthodontic archwire. During treatment, the archwire is secured within the slots and passageways of the brackets and molar tubes. While the archwire is initially distorted, it gradually returns to its original shape over the course of treatment, thereby applying therapeutic forces to urge the malpositioned teeth to proper locations.
Brackets, molar tubes, and other bondable appliances are generally affixed to teeth using a suitable orthodontic adhesive. Traditionally, adhesives were painstakingly applied, one at a time, to each appliance by an orthodontic assistant at the orthodontic office. Since this can be a tedious process, manufacturers have provided appliances that are coated in advance, or “pre-coated,” at the factory to save time for the orthodontist. Coated appliance configurations are described in detail in issued U.S. Pat. No. 4,978,007 (Jacobs, et al.), U.S. Pat. No. 5,015,180 (Randklev), and U.S. Pat. No. 5,328,363 (Chester et al.).
Pre-coated brackets and molar tubes provide a significant advantage to the practitioner. First, these appliances provide for a high degree of precision in the amount of adhesive that is dispensed on the base of each appliance compared with hand-coating appliances. Second, these appliances are easy to use and save time, since a practitioner can conveniently remove a bracket from its respective container and place it directly on the patient's tooth without need for intervening steps. Typically, the adhesive is a light curable adhesive which allows the appliance, once placed on the tooth surface, to be carefully positioned in a proper orientation before a curing lamp is activated to cure the adhesive and securely fix the appliance in place.
Various approaches have been taken in packaging adhesive-coated orthodontic appliances. In one approach, the appliance and adhesive are placed in a sealed “blister” or similar disposable container. The adhesive is secured against a wall of the container having a suitable release surface such that the appliance and adhesive lift off together when the appliance is plucked from the container. This approach is described in, for example, issued U.S. Pat. No. 6,183,249 (Brennan, et al.). Another approach involves using mechanical structures to suspend the appliance in the container such that the adhesive does not contact any surfaces of the container. Examples of this approach are described in issued U.S. Pat. No. 5,827,058 (Kelly, et al.) and U.S. Pat. No. 6,089,861 (Kelly, et al.), as well as International Publication WO/2013/162975 (Conley, et al.).